Steam-engine.



l.. J. TODD.

STEAM ENGINE. APPLICATION FILED MAR. 16. 191s.

1,23%?4?. Patented Sept. 11, 1917.

6 SHEETS-SHEET I.

ATTORNEY L. J. TODD.

STEAM ENGINE. APPLlcAfloN FILED MAR. i6. 1915.

Patented Sept. 11, 191?.

lNvENTon:

ATTORNEY.

L. J. TODD.

STEAM ENGINE.

APPLICATION FILED IIIAII. I6', 1916.

Patentedlsept. 11,191?.

6 SHEETS-SHEET 3 hmmm INVENTORI LJ. To D D 4 www ATTORNEY L. I. TODD.

STEAM ENGINE. APPucATloN FILEDMAR. le. wie.

Patented Sept. 1I, 1917.

6 SHEETS-SHEET 4- lN'vEN-rom L .J. Ton D A-r-rorwsv L. J. TODD.

STEAM ENGINE. APPLlATaoN FILED MAH. 16. |916.

Patented Sept. l1, 191?.

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IL. J. TODD. STEAM ENGINE. APPLICATION me MAH. 1e. |916.

Patented @apt 11, 191?,

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LEONARD JENNETT TODD, F STOKE NEWINGTON', LONDON, ENGLAND.

STEAM-ENGINE.

- following is a specification.

This invention refers vmainly to a :single driving handle and mechanism connected therewlth, which -controls a combined shutoff and expansion andreversing gear, in

` arrangements fully described, by way `of eX-4 such a manner Vas to be practically applicable to steam, compressed air, and the like.

As applied tosteam locomotives, or other elastic fluidengines worked by a direct hand control, the invention possesses-the following general features z-f 1. 'The operation of any such engine is made similar in simplicity and ease of manipulation, to that of an electric motor.

2. All variations-inthe power of the engine arecaused byl altering the rate of eX-' pansion, so that the engine is always worked with the greatest degree of expansion, and therefore of economy.v

3. The economic working of the engine is rendered largely independent of the skill of the operating engineer.

4. This method of working is capable 'of effecting a. great amountfof economy in fuel and water. L A

Sin le drivin" handle sto -eX anslon and reversing' mechanisms as hitherto proposed,

are inapplicable tol steam locomotives; on account of theI great Anumber and complexity 'of their working parts,l and the unsatisfac tory nature of their'zaction. But all these difficulties are entirely removed by the present invention.

For' the purposes above named my improved control gearcomprises features and ample, hereinafter. Y y

This specification is illustrated in the accompanyingsix sheets of drawings, containing six figures; in which the letters and nu'- mcrals of reference have the same signification throughout.

Figure 1 shows a general sectional, longitudinal elevation of the invention, with a single hand lever controlling a combined shut-ofi' and expansion and reversing gear,

through the medium of a power relay; as

applied to a dual-exhaust cylinder.

Fig. 2 shows a line diagramof the valve Specification of Letters Patent. Pmtntedl Spt, 2in1, 191% Application filed March 16, 1916. Serial No. 84,626.

control gear of the. invention, with the valves which admit the working f'luid full-shut.

Fig. 3, showsa line diagram of the valve control gear, with the valves which admit the working f'luid full-open.

Fig. 4 showsa general sectional, longitudinal elevation of the invention, with a single hand lever controlling a combined shutofl" and expansion vand reversing gear, through the medium of a lpower relay; as applied to an ordinary type cylinder.

Fig. 5 shows a general sectional, longitudinal elevation of the invention; with aV single handvle'ver directly controlling a combined shut-0H and expansion and reversing gear; as applied to a small dual-exhaust cylinder.

Fig. 6 shows the complete Valve control action, that is given 'by the single driving In Fig. 2 the line A B represents the longitudinal center line of th-e engine, on which the main dual-exhaust cylinder J is placed, which has its major exhaust release at V, caused by the main piston J1, and which has its 'minor exhaust release at V1 and V1, caused by the ordinary piston valve P. And

parallel to this first line is a second center line C D, on which is placed the valve control gear, which shutsoff the working fluid, and also varies the admission of the same to the cylinderd.

On the lineC D are placed two control pivots marked 4 and l--which either mayor may not also form the spindles of vibrating valves. And between the transverse center lines of the two ivots, that lie at right angles to the line D, and on either side of the control line-'C D, is placed a variable mot-ion joint marked .1. This has a longitudinal motion to and fro, substantially par allel to the line C D; and inl a reversing engine, either in agreement with vthe motion of the main piston'J 1, or in opposition to the same; the latter being preferable. This motion may be given by an eccentric, or other mechanism, or may be conveniently derived -from the main crosshead 110,v by means of the link 11, the reducing leverv 12, and the rod 13. l

The variable control lio'int 1, has also a transverse motion, substantially at right angles to the line C D, regulatedby the lever 7 which is connected to it by the link 8; So that the joint 1 moves within the limits of the contour E F G H, in a series of longitudinal paths, as may be determined farther from the line C D. And this contour, most suitably, lies altogether on either one side or the other of the line C D, on

which the two control pivots 4 and 4 are situated.

On the control pivots 4 and 4 are fitted levers 3 and 3, which, most suitably, lie on the opposite side of the line C D, to that on which the control contour E F G H is placed, and the levers are connected to the control joint 1 by the links marked 2 and 2.

The main cylinder J has a primary cutoff valve at each end, of any suitable kind, but preferably of the vibrating class, as shown at 5 and 5 in Fig. 2. According to this arrangement the control pivots 4 and 4, also l form the spindles of the valves 5 and 5-but this is not necessarily the case. These valves cut off the working fluid from the `ports 6 and 6, at their outside edges; that is, at the edges of the two ports that are farthest from the central lcontrol joint 1. And this mechanism is capable of giving the following actions If the control joint 1 be moved close to the line C D, and consequently to the bottom of the contour, at E F, as shown in this Fig. 2:-Then the links 2 and 2 move the levers 3 andy 3, so as to cause the valves 5 and 5, to entirely close the ports 6 and 6. And then the joint l may rock the valves 5 and 5 to and fro through the action of the rod 13; but yet they will not uncover the ports 6 and 6, by any pre-arranged minimum distance, say half-an-inch. And thus, in that position of the control joint 1, the valves 5 and 5 form an absolute shutoff gear. A

Then again :-The control joint 1 might be moved 'from its position vof shut to the position marked O, on the sector of Fig. 2, which radiates from the lever 7. When the links 2 and 2 would pull the levers 3 and 3 inward, and so move the cut-off edges of the valves 5 and 5, toward the outside cut-off edges of the ports 6 and 6. And then the valves might vibrate to and fro, with their cut-off edges just coming to the cut-olf edges of the ports; but without any admission of the working fluid being actually given.

Or The control joint 1 might be moved farther upward, so as to give the admission of 10 per cent. at the beginning of each stroke of the main piston J1. Or, it might be moved' still farther upward, so as to give 20 per cent. of admission. Or it might be movedv still farther, so as togive 3() per cent., or 40, 50, 60, 7 0 or 8O per cent. admission. Until finally, when 'the control joint l had been -moved to the eXtreme top of the contour at G H it would give the admission of 90 per cent. from the commencement of each stroke of the piston J1. And

then the valve gear and the admission valves 5 and 5 would have changed to the positions shown in Fig. 3.

The contour E F G H as shown in Fig. 2 is not symmetrical in shape, and hence the joint 1 would have a movement to some extent unequal, which if uncorrected, would give an unequal admission to the two ends of the cylinder J. And in order to equalize this r-The end of the lever 7 to which the joint 1 is connected by the link 8, is caused to move in an arc marked "71,l so as to alter the vibrating point of the lifting link 8, in such a way as to give therequired equality of admission. And the curvature of this are is found in a similar manner, to that employed to equalize the action of an ordinary reversing gear; that is, points are experimentally found, through which the required curve is then caused to pass.

And the result. is that the admission at each end of the cylinder J, can be made absolutely equal, all the way from 0 to 90 per cent. And as the motion joint 1 is driven in direct opposition to the motion of the main piston J1, this equality of action is the same, with either directionAof rotation.

The primary valves 5 and 5, as controlled by the variable joint 1,` and when used for hand control, thus act as a positive shut-oli' gear, and also give any desiredv variation in either the closure, or the termination of the yadmission of the Working liuid; but they do not provide for the correct commencement of the admission to the main cylinder J. Nor do they provide for the release of the Whole of the waste Working fluid from an ordinary cylinder; or for the release of the residual part of the same from the dualexhaust cylinder J; and therefore a secondary valve, or valves, must be provided to give these necessary requirements.

This secondary valve or valves, may be of any suitable kind, butis preferably a'piston valve, which is marked P in Fig. 2. It is arranged to give the correct commencement of the admission of the working fluid to the main cylinder J; and also to give a suitable release to either the whole, or the residual part of the waste working fluid, as may be required.

The direction in which the crankshaft, marked 100 in Figs. 1, 4 and 5, shall turn, is determined by any suitable reversing gear, being applied to the secondary valve P; say such as that shown at 120, and which is varied by a lever, or handle, marked 21.

In order to bring the action of the primary valves 5 and 5, and the action of the secondary valve P into a single lever hand control, the variable control joint 1 is connected to and adjusted by the reversing lever, or handle 21, in such a Way that When the reversing handle stands in its central position, the variable control joint 1, holds the primary valves at full-shut; and

.when the reversing handle is moved to they meet at N; the link L being suspended from a iixed center at K, and the link M being jointed to the' lifting lever 7 which is connected to the control joint 1 by the links 8. The reversing handle, or lever, which moves the reversing gear connected to the valve P, is shown at 21; and a rod marked 14:, is carried from it to the elbow link L, as shown.

With this mechanism arranged as shown in Fig. 2*:-When the reversing handle stands in its central position at shut, the rod 14 holds the elbow links L and M in a straight line, so that the lifting lever 7 and also the control joint 1, are held down, also in their positions of full shut Then, supposing the reversing lever to be moved to its full back position, the rod 14 will move the joint N, to the position X; when the link M will draw the lifting lever 7 and the control joint 1, to their extreme height of 90 per cent. admission. And then'the reversing lever 21, the elbow joint L M, the valvecontrol gear, and the admission valves 5 and 5, will occupy the positions shown in Fig. 3.

And the same result will be produced by moving the reversing' lever to its eXtreme fore7 position; for then the joint N will be moved to the position of Y, which will obviously 'open the admission to precisely 90 per cent. as before.

So that by moving the reversing lever 21 either forward or backward, as maybe desired, any amount of graduated admission of the working fluid can be given by the valves 5 and 5, all the Way from 0`to 90 per cent., and this with either direction of rotation. And by bringing the reversing lever 21 into its central position, the valves 5 and 5, are always moved back to full shut suppression, as shown in Fig. 2.

This mechanism for thus adjusting the control joint 1, and for combining the advmission of the working fluid, as controlled by the lever 7, and the reversing of the en gine, as controlled by the lever 21, into al single driving handle control, may be varied, provided always that :-`When the reversing handle 21 stands in its central position, the variable control joint 1 holds the primary valves 5 and 5 at full-shut; and when the reversing handle 21 is moved to either fullforeor full-back gear, the control joint 1 moves the primary valves 5 and 5 to fullopen.

The valve control joint 1 may have its shut position either at E F near to the control line C D; or at G H, at the farthest distance from the control line. It is however better to have the shut position near to the line C D, as shown in Fig. 2. As then, when the joint 1 is moved away from E F, the control gear at first gives but little motion to the levers 3 and 3; which makes a relatively long distance from the full shut position, to the commencement of the 0 per cent. admission, as shown on the sector of Fig. 2, which radiates from the lever 7. And it also causes the distances between the percentages of admission to be greater at the early stages, and to be gradually reduced as the eXtreme of 90 per cent. admission is approached.

This considerable 4distance from shut to the 0 position of admission, is further increased by the action of the elbow links L and M; so that when this action comes to be transferred to the lever 21, by` means of the rod 14, it may be seen that this reversing lever 21, moves through about one-half of its distance, from its central position of shut before the 0 position of admission is reached, von its way to either fore or back full gear.

The object in having the reversing lever 21 to'move about one-half of its travel, from its central position, before the 0 position of admission is reached, and the valves 5 and 5' commence to open is z-That the piston valve P may then have its minor exhaust release moved over to full gear, before the admission by the valves 5 and 5 commences. With the consequence that the minor exhaust-release by the valve P, never takes placse earlier than the major exhaust-release by the main piston J1, while the working Huid is being admitted by the valves 5 and 5. Also, the compression of the residual waste working fluid, is then always moderate in amount. And in addition, the piston valve of a dual-exhaust cylinder, can then be made very small in diameter, as herein af terward further explained.

` These features of the steam distribution are'illustrated in Fig. 6, by the percentages radiating in a sector from the lever 21, which shows the variations of action that are produced by simply moving the single driving handle to and fro, from its central position of shut, to either the fore or back full gear, as may be desired.

The rst row of these percentages marked R, shows the varying admissions of the working fluid, produced by the primary valves 5 and 5.

The second row marked S, shows the corresponding admissions, which at the .same times are given by the secondary piston valve P.

The third row marked T shows the earlivest openings of the exhaust-release, during the whole period of admission, from to 90 per cent. The release shown'of 90 per cent. is the major exhaust-release, caused by the main piston at V; the minor exhaustrelease, caused by the valve P, atV1 and V1, being always later than this 90 per cent. And so this minor exhaust-release by the piston valve P, always remains in full open gear, however the ratio of expansion may be varied; and is automatically prevented from to give counter-admission, in order to facilitate braking, sudden stoppage, or very quick reversal. And alsoA the engine cannot then be readily started in an un-desired direction; as may easily be done when the admission gear, and the reversing gear, are worked by separate handles.

j In a large or medium engine as shown in Fig. 1, the single lever 21, which controls the primary admission valves and the secondary reversing valve, may be moved by 4a power relay cylinder marked 25, worked by.

a small driving handle 26; which handle may be moved by a small quick-pitch screw, if so desired. Or th'e lever 21 may be moved directly by an ordinary screw reversing m0- tion.

In a small engine, as shown in fig. 5, the single control lever 21 may be moved directly by a hand lever 27; which will then also give the variations of action, that have been detailed.

The said control gear, as applied to a dualexhaust cylinder J, possesses the following advantages over its application to an ordinary cylinder Q:

A much smaller piston valve.

A much smaller waste clearance.

A greatly increased ratio of expansion.

A much larger exhaust-release area.

A much larger indicator diagram.

A greatly increased effective power.

A much greater eiciency.

And the said invention enables the econ- 1 carried much further than is at present possible with such engines. It also enables the hot-water lifeless locopresent shows.

The invention is applicable' to engines which use steam, compressed air, or other elastic liuid; with either a simple expansion or other Aexpansive system of cylinders.`

The invention has been described hitherto as applicable to double-acting engines, buty it is equally applicable.to single-acting engines by merely omitting one of the pivots marked 4, and the lever, link, andvalve con-- nected therewith.

The numerical Afigures given in this specification, or shown in the accompanying drawings, in respect .topercentages .of admission, expansion, release, compression, or having reference to other features, are merely illustrative, and may be varied.

What I claim and desire to secure by Letters Patent is l. A steam or other' elastic uid engine comprising the elements of a combined shutol and expansion gear.. including -primary expansion valves, a secondary admitting and exhausting valve adapted to receive working fluidfrom the primary` valves, a main driving dual-exhaust cylinder adapted to receive working fluid from the secondary valve, a reversing gear connected` to the secondary valve and a single controlling hanf dle connected tothe primary expansionl valves, and also to the reversing gear of the secondary valve, the whole being correlated to give a single handle control of the shutoff and expansion of the working fluid by the primary valves, and of the direction of lthe rotation of the engine by the secondary valve.

2. A steam or other elastic Huid enginev comprising the elements of a primary shutoil and expansion gear including two pivotal ioo axes, a variable control driving joint located between the transverse center lines of the axes that lie at right angles to a line connecting the said axes, driving levers oscillating about the said axes, diagonal-driving links connecting the said levers with the variable control drivin joint, primary shutoil' and expansion va ves connected either directly or indirectly to the said pivotal axes, a secondary valve adapted to receive working fluid from the primary valves, a main driving cylinder adapted to receive the working fluid from the secondary valve, a reversing gear connected to the secondary valve, and a single controlling handle connected to the variable control joint of the primary valves, and also to the reversing gear of the secondary valve, the whole being -correlated to give a single handle control of the shut-off and expansion of the work-3 ing fluid by the primary valves, and of the direction of the rotation of the engine by the secondary valve.

3. A steam or other elastic fluid engine comprising the elements of a primary shutolf and expansion gear including two pivotal axes, a variable control driving joint located between the transverse center lines of the axes that lie at right angles to a line connecting the said axes, driving levers oscillating about the said axes, diagonal driving links connecting the said levers with the variable control driving joint, primary shutoH and expansion valves connected either directly or indirectly to the said pivotal axes, a secondary admitting and exhausting valve adapted to receive workingvluid from the primary Valves, a main driving dualeXhaust c linder adapted to receive the working uid from the secondary valve, a reversing gear connected to the secondary valve, and a single controlling handle connected to the variable control -joint of the @primary valves, and also to the .reversing gear of the secondary valve, the whole being correlated to give a single handle control of the shut-oil and expansion of the working fluid by the primary valves, and of the direction of the rotation of the engine bythe secondary valve.

` 4. A steam or other elastic Huid enginev comprising the elements of a primary expansion gear including two pivotal axes, a variable control driving joint located between the transverse center lines of the axes that lie at right angles to a line connecting the said axes, diagonal driving links connecting the said levers with the control driving joint, primary expansion valves connected to the said pivotal axes, a secondary admitting and exhausting valve, adapted to receive Working fluid from the primary valves, and a main driving dual-exhaust cylinder adapted to receive the working fluid from the secondary valve, the whole being correlated to control the Working fluid by means of the primary valves, by means of the secondary valve, and by means of the dual-exhaust cylinder main piston.

In testimony whereof I have affixed my signature.

,LEONARD JENNETT TODD. 

